In two dimensional to three dimensional video conversion, depth information is extracted from input pictures of the two dimensional video in order to generate a pair of stereo output pictures. Extracting depth information is a key step in the two dimensional to three dimensional conversion process.
Preconstructed three dimensional video, such as the video displayed at properly equipped movie theaters, considers the three dimensional aspects of the video from the start. Essentially, three dimensional processing technicians can properly isolate objects in a scene and place these objects in a depth map along the z-axis. Because these are preconstructed videos, the technicians have the benefit of knowing when objects will enter into the video both before and after the present image of the video. This knowledge allows these technicians to properly place these objects in the depth map.
However, in many instances, converting two dimensional video to three dimensional video, such as converting broadcast video into three dimensional video, is much more difficult, particularly when it is done in real time. Unlike preconstructed three dimensional movies, there are no technicians that have preprocessed the video with the knowledge of which objects will enter the scene or leave the scene. Accordingly, it is very difficult to properly identify objects and place these objects in a depth map.